This invention relates to the art of electromagnetically operated fluid pumps and more particularly to a new and improved electromagnetic pump which operates at extremely low power.
One area of use of the present invention is implantable drug delivery systems, although the principles of the present invention can be variously applied. The principal requirements for a pump in such applications are low power drain, since the pump must be driven by an implanted battery, and compatibility with the drug being pumped. Another important requirement is that the pump be capable of operating with bubbles present in the liquid being pumped. In addition, there is the desirability of achieving increased maximum available pumping rate, some relaxation of tolerances between certain parts of the pump, pumping against higher back pressures without saturating the pump magnetic circuit, and improved stability of stroke volume.
It would therefore, be highly desirable to provide an electromagnetically-operated pump which is safe, reliable, small in size, light in weight which operates without excessive demand on the available energy supply, which is compatible with drugs or similar liquids to be pumped, which is capable of operating with bubbles present in the liquid being pumped, which has an increased maximum available pumping rate, wherein tolerances between some of the parts thereof are relaxed, which pumps against higher back pressure without saturating the pump magnetic circuit, and which has an improved stability of stroke volume.